How good is he?

Only five players in history have ended their careers with a higher figure than Smith’s 60.37. By way of comparison, India legend Sachin Tendulkar averaged a shade under 54, Brian Lara 53 and Sir Viv Richards 50.

“He’s an outstanding player. His record speaks for itself,” said England’s leading wicket-taker James Anderson, part of the attack that failed to dislodge Smith in 51.3 overs on Friday.

Smith is unrecognisable from the player – a leg-spinner who could bat – who said his role when he was called up for the Ashes in 2010-11 was to “bring a bit of fun”.

Leadership has burnished rather than burdened his statistics. He scored three centuries in his first three games in charge when deputising for Michael Clarke in 2014, a move which was made permanent the following year.

Smith averages 70 as captain. He averages 80 as captain in Australia. In the past year, as captain in Australia – England bowlers are advised to look away now – Smith averages 100.

“Players like that sucker you into bowling too straight and, before you know it, you’re being hit into the leg side.”

Smith scored only eight runs on the off side by the time he got to 50 at the Gabba on Friday, instead favouring firm drives past mid-on, wristy flicks to mid-wicket and deft leg glances.

Former opening batsman Geoffrey Boycott, who played 108 Tests for England, told BBC Test Match Special: “He looks a bit of an ugly duckling. He’s not an aesthetic player but he’s a very effective player.”

So how do you get Smith out?

It is a question that troubled England’s bowling attack long before they landed in Australia.

“We’ve spoken a lot about him because he’s their best player,” said Anderson.

Former Australia seamer Glenn McGrath, who took 563 wickets in 124 Tests, told TMS: “If I was bowling to Steve Smith, I’d just try to hit the top of off, find the edge. Keep it simple.”

Ex-England batsman Ian Bell, a three-time Ashes winner, told BBC Radio 5 live: “We got him caught behind and in the slips a few times when he went after the ball, but today he left unbelievably well.”

Boycott’s advice: “I would bowl straight – to his strength – but pack the on side.” England tried these tactics on Friday – without success.

Bell added: “He does become an lbw candidate, but the problem when you go straight is that he’s probably the best player in the world off his pads.

“It is a very, very fine line. The margin for errors are so small.”

Anderson suggested not complicating matters too much. “You’ve almost got to try and take him out of the equation and concentrate solely on where you want the ball to pitch,” he said.

“No good player likes to be calmed,” former opener Graham Gooch, who scored 8,900 Test runs for England, told 5 live.

“What you have to do is put pressure on him – dry up the runs, stop him scoring – and hopefully he might make a mistake.”

What happens if England don’t get him out?

Smith did not offer a chance on Friday. An edge off Moeen Ali which fell short of slip and a top-edged pull which landed safely between two men stationed on the leg-side boundary were the closest England came to removing him.

“If Smith gets a hundred, Australia will get a lead and the pressure of that first innings will be immense for England,” said Vaughan.

Agnew said: “Even a small first-innings lead should be significant.”

When Peter Handscomb’s dismissal left Australia 76-4, the likelihood of an England win was rated at 68% and an Australia victory 23%. By the time Smith left the field alongside Shaun Marsh, their partnership worth 89, Australia were considered favourites.

Boycott said: “You have to take your hat off to Steve Smith – the lad knows his own game.

“He reminds me of Rahul Dravid. Once he got in, it felt like he’d never get out.”

Of Smith’s 20 Test centuries, five have come against England.

If his improvement in Ashes series continues, there may well be more to come this winter.